There is no way to restart immediately, but you can wait for your colony to be deleted over time
It takes 8 days for a normal colony to be deleted
And it takes 16 days for a supporter's colony to be deleted
If you log on before 8(or 16) days are up the days will be reset and you'll have to wait another 8(or 16) days for your colony to be deleted
After your colony is deleted you can start over again on that world. But keep in mind it's a real time game so ticks won't wait for you

--Also if you're in vacation mode your colony won't be deleted--